1. Technical Field
This invention relates to suspension assemblies and, more particularly, to a pulley suspension assembly for assisting a user to vertically transport a cable to an elevated location.
2. Prior Art
Prior devices for supporting scaffolds have utilized fixed supports anchored to side wall columns or other structural members, requiring dismantling of same to move the scaffolds to required new positions. This is the time consuming and inefficient. Floor supported scaffolds have been used on some buildings wherein relatively low side walls are involved, however these must also be dismantled and moved as work progresses along the side wall. It is known in the art to provide suspended scaffolding for working at elevated heights, however, suitable suspension means are still lacking.
U.S. Pat. No. 4,074,789 to Warren discloses a rolling support for moving scaffolding alongside the side or end of a building under construction. The support includes a frame structure which rigidly connects a leading outrigger and a trailing outrigger together. Each of such outriggers has a near-side traveling wheel to ride on an exposed structural roof member adjacent the side or end of a building, and a far side force roller which extends beneath a parallel exposed structural roof member inwardly from the side or end of the building. The outriggers are parallel to one another and ride on parallel exposed structural roof members. The near-side travel wheel bears down on its exposed roof member and exerts substantial downward pressure thereon while the far-side force roller bears upwardly against the underside of its exposed roof member. Remote controlled motor means are mounted on the frame so as to drive the near-side traveling wheel. Unfortunately, this prior art reference does not provide a lightweight, compact, and portable means of assisting a user to transport scaffold cable onto an elevated surface.
U.S. Pat. No. 4,309,023 to Plumettaz discloses an apparatus for suspending a scaffold or the like, used for working on the outer walls of buildings. The apparatus comprises a capstan made up of four pairs of pulleys driven by an electric motor. The pulleys have grooves for receiving suspension cables, each of which is wound over a pair of pulleys in five turns. On the slack-portion side, each cable is guided over a traverse mechanism, then runs onto a reel mounted via friction couplings on a shaft. This shaft is driven by the motor when the scaffold is raised, while during the descent it is locked by a mono-directional coupling, a driving wheel then being free on the shaft. A safety release device intended to intervene in case of lessening of the tractive force yielded by the friction couplings is combined with the traverse mechanism. If the tension of the slack portion of cable drops below a given threshold, a safety release cuts off the current supply to the motor and actuates an electromagnetic brake. Unfortunately, this prior art reference intended to mount and hold an elevated scaffolding and not to assist a user in guiding and transporting scaffold cable onto a rooftop.
U.S. Pat. No. 4,441,849 to Dizmang discloses a light weight carriage having a flat bed and a pivotal ramp. The carriage includes a winch and counterbalance assembly which is first hauled to the roof of a building or other elevated location. Gutter guards are then installed to the carriage, and the ramp is placed in its supported inclined position. A separate platform or pallet to which a load is attached, and having a plurality of small wheels thereunder, is connected to the cable of the winch on the carriage and is winched up the wall of the building, over the gutter guards, over a wheel-protecting block on the ramp and into its final position on the ramp. The ramp is thereafter lowered and the assembly is used like a dolly to move the load to its final location. Unfortunately, this prior art reference does not disclose a plurality of pulleys and guides to safely direct a cable pulled therethrough while reducing frictional contact and the required labor need to raise heavy cable.
Another prior art example includes a drum that has a circular-grooved surface on which a cable reserve is wound. One end of the cable is secured to the drum, which rotates while being driven by a control motor in one direction or the other, depending upon whether the scaffold is to be raised or lowered. Thus, the scaffold is connected to the support at a fixed point to which one end of the cable is attached. Such a drum assembly is extremely bulky, for the cable reserve must be laid down in a single layer on the drum, and this leads to extremely large-sized drums. The large size of the drum complicates the construction of the winch and increases its weight, and this can complicate the arrangement of the track provided at the top of the wall for displacing the support.
Accordingly, a need remains for a pulley suspension assembly in order to overcome the above-noted shortcomings. The present invention satisfies such a need by providing an assembly that is convenient and easy to use, is durable yet lightweight in design, is versatile in its applications, and provides a means for assisting a user to vertically transport a cable to an elevated location.